GB2072861A - Earth leakage circuit breaker tester - Google Patents
Earth leakage circuit breaker tester Download PDFInfo
- Publication number
- GB2072861A GB2072861A GB8006194A GB8006194A GB2072861A GB 2072861 A GB2072861 A GB 2072861A GB 8006194 A GB8006194 A GB 8006194A GB 8006194 A GB8006194 A GB 8006194A GB 2072861 A GB2072861 A GB 2072861A
- Authority
- GB
- United Kingdom
- Prior art keywords
- earth leakage
- circuit breaker
- testing
- leakage circuit
- relay
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
- H02H3/33—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers
- H02H3/334—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial unbalance for other protection or monitoring reasons or remote control
- H02H3/335—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial unbalance for other protection or monitoring reasons or remote control the main function being self testing of the device
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
An earth leakage circuit breaker tester comprises a network of resistors 12 from which a resistor can be selected by a switch 13 to give one of a number of preselected breaker tripping currents from a supply to which the network is connected. The network is also connected through the movable arm of switch 13 to one contact of the contacts of a relay R which is controlled by means of a timing circuit 6 to close a supply circuit 12 from the network to the breaker under test for a preset time. Resistors 3, 4 and a capacitor 5 govern the preset time and a variable resistor 8 is provided for calibrating the circuit 6. The arrangement provides for testing the satisfactory operation of earth leakage circuit breakers over a range of currents and times. <IMAGE>
Description
SPECIFICATION
Earth leakage circuit breaker tester
The present invention relates to apparatus for testing an earth leakage circuit breaker.
Industrial, commercial and domestic electricity distribution systems generally include an earth leakage circuit breaker to protect both personnel and equipment from the effects of excessive earth leakage currents. An earth leakage circuit breaker consists of a switch which is automatically opened in as short a time as is possible when earth leakage currents exceed a pre-determined level.
Most earth leakage circuit breakers include a test button, with instructions for operation at least once monthly. This button simply applies an earth leakage current to the system of greater magnitude than that required to trip the breaker which is designed to test the mechanical operation of the switch. In cases where an earth leakage circuit breaker is utilised to offer a degree of protection to personnel, it is important that the earth leakage circuit breaker should open very rapidly. British Standard 4293; 1968 is a specification for current operated earth leakage circuit breakers. Within this specification an earth leakage circuit breaker shall operate within the limits of 50% and 100% of the rated tripping current within 0.1 of a second.In practice it is desirable that the earth leakage circuit breaker shall operate in considerably less than this time and a more practical speed of operation is .03 of a second.
According to the present invention; there is
provided apparatus for testing an earth leakage
circuit breaker comprising means for feeding a
selected one of a number of tripping currents to
the breaker, and means for varying the time that
the selected current is fed whereby to enable the
operation of the circuit breaker at a preselected
tripping current within a preselected time to be
checked.
The apparatus may be plugged into any socket
outlet which is fed from an earth leakage circuit
breaker and upon operation of a push-button will
apply an earth fault current the pre-selected
magnitude, for the preselected length of time, to
the system whereupon the breaker should open.
An additional problem which is occasionally
encountered in systems protected by earth
leakage circuit breakers is that of spurious
tripping. Spurious tripping may be defined as
tripping of the circuit breaker with earth leakage
currents of less than 50% of the rated tripping
current. Resistance to this spurious tripping may
be tested for by applying an earth leakage current
of 50% of the rated tripping current and ensuring
the breaker does not trip. In a preferred and
advantageous modification of the invention,
therefor, the range provided by the means for
feeding a selected one of a number of tripping
currents to the breaker is broad enough to
encompass a tripping current of 50% of the rated
tripping current.
In order that the present invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the single figure of the accompanying drawing which shows a circuit diagram of a testing apparatus for an earth leakage circuit breaker.
Referring to the drawing, the circuit basically comprises two parts. A first part referenced A which controls the time for which testing an earth leakage tripping current is to be supplied and a second part referenced B which controls the magnitude of the testing earth leakage tripping current. Part A of the circuit comprises a timing device in the form of an integrated circuit 6. A time selector.switch 7 is connected across two inputs of the circuit 6. Associated with the switch 7 is a time selection circuit comprising resistors 3 and 4 and capacitor 5. A push button operating switch 1 is connected across two of the terminals of the timing device 6. The timing device 6 may be calibrated by means of a variable resistor 8.
The output from the timing device 6 is connected through a light emitting diode (LED) 9 to the coil R of a relay 2. A diode 1 5 is connected in parallel with the relay coil.
Part B of the circuit comprises a resistive network 12 comprising eight resistors which are respectively connected to the eight terminals of an eight position selector switch 1 3. The resistive network 12 as a whole is connected between the movable arm of the selector switch 1 3 and the contacts 11 of the relay 2. The other terminal of the contacts 11 is connected to the live terminal of the supply and a neon indicator lamp 10 is connected between the live terminal and earth.
In operation of the circuit, the push-button 1 is operated to produce an earth fault leakage current. The duration of this current is dependant upon the position of the selector switch 7 and upon the values of the resistors 3 and 4 and capacitor 5. The existence of a fault current and therefore an indication of the proper operation of the tester is given by the light emitting diode 9 lighting up. On operation of the push-button 1, current is therefore fed to the relay coil R of the relay 2 and, as a result, the relay contacts 11 close. The magnitude of the earth fault leakage current is determined by the amount of resistance in the live line of the circuit provided by the resistive network 12 depending upon the position of the switch 13. This position is previously selected having regard to the rated tripping current of the earth leakage circuit breaker under test.If this circuit breaker is operating correctly, it will trip out within the time duration set at the tripping current selected.
To test for spurious tripping of an earth leakage circuit breaker, the position of the switch 13 appropriate to an earth fault leakage current of less than 50% of the rated tripping current is chosen. If the breaker trips out at this low tripping current, it is unsatisfactory.
It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, although in the resistive network 12 eight individual resistors have been connected in four branches with two resistors to each branch to cater for four basic ranges of tripping current with either 50% or 100% of the tripping current selected, other forms of resistive network may equally well be used. The resistive network arrangement described in the above embodiment is felt to give a reasonable testing facility having regard to the practice presently adopted by manufacturers of earth leakage circuit breakers as it is the common practice for such manufacturers to adopt standard tripping currents.
Claims (9)
1. Apparatus for testing an earth leakage circuit breaker comprising means for feeding a selected one of a number of tripping currents to the breaker, and means for varying the time that the selected current is fed whereby to enable the operation of the circuit breaker at a preselected tripping current within a preselected time to be checked.
2. Apparatus for testing an earth leakage circuit breaker as claimed in Claim 1, in which the means for varying the time comprises a timer, a time selection switch connected to the input to the timer and a time selection circuit associated with the time selection switch.
3. Apparatus for testing an earth leakage circuit breaker as claimed in Claim 2, in which the time selection circuit comprises resistors and a capacitor to partly determine the time for which current is to be supplied.
4. Apparatus for testing an earth leakage circuit breaker as claimed in Claim 2 or 3, in which a variable resistor is connected to the timer to enable the timer to be calibrated.
5. Apparatus for testing an earth leakage circuit breaker as claimed in Claim 2, 3 or 4, in which the timer is an integrated circuit.
6. Apparatus for testing an earth leakage circuit breaker as claimed in any of claims 2 to 5, in which the output of the timer is connected to a relay to operate the relay for the time selected.
7. Apparatus for testing an earth leakage circuit breaker as claimed in Claim 6, in which the means for feeding comprises a network of resistors which is connected between the movable arm of a resistor selector switch and one of the contacts of the relay, the other relay contact being adapted to be connected to the live supply.
8. Apparatus for testing an earth leakage circuit breaker as claimed in Claim 6 or 7, in which a light emitting diode is connected in parallel with the coil of the relay to indicate when the relay is energised.
9. Apparatus for testing an earth leakage circuit breaker substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8006194A GB2072861A (en) | 1980-02-23 | 1980-02-23 | Earth leakage circuit breaker tester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8006194A GB2072861A (en) | 1980-02-23 | 1980-02-23 | Earth leakage circuit breaker tester |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2072861A true GB2072861A (en) | 1981-10-07 |
Family
ID=10511628
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8006194A Withdrawn GB2072861A (en) | 1980-02-23 | 1980-02-23 | Earth leakage circuit breaker tester |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2072861A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2118310A (en) * | 1982-04-08 | 1983-10-26 | Avo Limited | An instrument for testing circuit breakers |
| GB2124786A (en) * | 1982-08-03 | 1984-02-22 | British Nuclear Fuels Ltd | Testing device for circuit breakers |
| EP0506602A2 (en) * | 1991-03-27 | 1992-09-30 | Amit Electronics And Engineering Ltd. | Device and method for GFCI time response and ground test |
| NL1009293C2 (en) * | 1998-05-29 | 1999-11-30 | Holec Holland Nv | Test circuit with time-limited fault current for a protection device. |
| GB2456799A (en) * | 2008-01-24 | 2009-07-29 | Andrew Abbott | Residual current device test actuator |
| WO2011041835A1 (en) * | 2009-10-06 | 2011-04-14 | Easytest Pty Ltd | Portable earth leakage tester |
-
1980
- 1980-02-23 GB GB8006194A patent/GB2072861A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2118310A (en) * | 1982-04-08 | 1983-10-26 | Avo Limited | An instrument for testing circuit breakers |
| GB2124786A (en) * | 1982-08-03 | 1984-02-22 | British Nuclear Fuels Ltd | Testing device for circuit breakers |
| EP0506602A2 (en) * | 1991-03-27 | 1992-09-30 | Amit Electronics And Engineering Ltd. | Device and method for GFCI time response and ground test |
| EP0506602A3 (en) * | 1991-03-27 | 1993-10-13 | Amit Electronics And Engineering Ltd. | Device and method for gfci time response and ground test |
| NL1009293C2 (en) * | 1998-05-29 | 1999-11-30 | Holec Holland Nv | Test circuit with time-limited fault current for a protection device. |
| EP0961129A1 (en) * | 1998-05-29 | 1999-12-01 | Holec Holland N.V. | Test circuit with time-limited fault current for a protection device |
| GB2456799A (en) * | 2008-01-24 | 2009-07-29 | Andrew Abbott | Residual current device test actuator |
| WO2011041835A1 (en) * | 2009-10-06 | 2011-04-14 | Easytest Pty Ltd | Portable earth leakage tester |
| AU2010305314B2 (en) * | 2009-10-06 | 2014-12-18 | Easytest Pty Ltd | Portable earth leakage tester |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |